Commit 7ad728f981
(cpumask: x86: convert cpu_sibling_map/cpu_core_map to cpumask_var_t)
changed the output of /proc/cpuinfo for siblings:
Example on an AMD Phenom:
physical id : 0
siblings : 1
core id : 3
cpu cores : 4
Before that commit it was:
physical id : 0
siblings : 4
core id : 3
cpu cores : 4
Instead of cpu_core_mask it now uses cpu_sibling_mask to count siblings.
This is due to the following hunk of above commit:
| --- a/arch/x86/kernel/cpu/proc.c
| +++ b/arch/x86/kernel/cpu/proc.c
| @@ -14,7 +14,7 @@ static void show_cpuinfo_core(struct seq_file *m, struct cpuinf
| if (c->x86_max_cores * smp_num_siblings > 1) {
| seq_printf(m, "physical id\t: %d\n", c->phys_proc_id);
| seq_printf(m, "siblings\t: %d\n",
| - cpus_weight(per_cpu(cpu_core_map, cpu)));
| + cpumask_weight(cpu_sibling_mask(cpu)));
| seq_printf(m, "core id\t\t: %d\n", c->cpu_core_id);
| seq_printf(m, "cpu cores\t: %d\n", c->booted_cores);
| seq_printf(m, "apicid\t\t: %d\n", c->apicid);
This was a mistake, because the impact line shows that this side-effect
was not anticipated:
Impact: reduce per-cpu size for CONFIG_CPUMASK_OFFSTACK=y
So revert the respective hunk to restore the old behavior.
[ Impact: fix sibling-info regression in /proc/cpuinfo ]
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090504182859.GA29045@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
35d11680a9